JPS608601A - Method and device for generating and reheating steam - Google Patents

Abstract

In a steam generation and reheat apparatus and method, after flowing in series through a superheater (72) and an evaporator (68) a heat supply fluid flows through both an economizer (60, 64) and a reheater (82, 94) in parallel flow to improve the Rankine Cycle thermal efficiency in plants such as nuclear power plants where the heat supply fluid temperatures are limited.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to steam generation and reheating systems, and more particularly, to steam generation and reheating systems for high pressure (H, P) heat engines in which a heat supply fluid is passed in heat exchange relationship with water and steam. (i.e. turbine) and recycle exhaust steam from the high pressure M engine until it is of suitable quality for feeding to the low EE (L, P) heat engine (i.e. turbine). This invention relates to a steam generation and reheating device for heating. "Quality" here
refers to the weight fraction or weight percentage of steam in a mixture of steam and water, and also refers to the degree of superheating of superheated steam.

Pressurized water reactor plants generally use a steam generation cycle in which a first fluid, referred to as a coolant, is passed in heat exchange relation to fuel rods located within the reactor core, thereby generating a heated coolant. is passed through a heat exchanger called a steam generator,
The feed water is heated by exchanging heat with the feed water flowing in the steam generator, and i-thermal steam is created. In such a once-through steam generator, the preheater, evaporator and superheater are not provided as separate units, but are combined into a 1 It- tube bundle. The functions of preheating, evaporation and superheating take place in the lower, middle and upper parts of the tube bundle, respectively, as the feed water and generated steam rise within the tube bundle. Exhaust steam from the high pressure turbine can also be passed into heat exchange relationship with the cooling fluid to reheat it to a quality suitable for delivery to the low pressure turbine.

In the nuclear reactor plant disclosed in US Pat. No. 4,164,849, the coolant in the fast breeder reactor is liquid sodium. The coolant is passed as a parallel 6fE flow through the superheat Δg and reheater in a manner typical of nuclear power plant reheat cycles, and then passed in series flow through the evaporator and preheater; It is returned to the reactor core.

In reporting reactor systems such as pressurized water reactors, fast breeder reactors, fusion reactors, etc., the humidity of the steam is
(cooling fluid) and the temperature range of the heat supply fluid as it imparts heat to the steam and water. To increase the thermal efficiency of the Rankine cycle, heat water at a higher average temperature, evaporate it, and create steam! It is well known to those skilled in the art that 4-heating is desirable and necessary. Therefore, to increase the thermal efficiency of the Rankine cycle, it is desirable to evaporate water at as high a pressure as possible, and thereby at as high a temperature as possible. However, increasing the steam pressure causes the so-called "pinch point ΔT problem." That is, if the vapor pressure, and therefore the corresponding evaporation temperature, is increased, this ΔT (the temperature difference between the two heat exchange fluids at a particular point during the cycle) becomes too small;
The log-average temperature difference within the economizer and evaporator sections of the steam generator cannot be maintained at a sufficient level for efficient heat transfer.

Such temperature limitations have made it difficult to design a power generation fusion reactor using an organic fluid coolant that can achieve the full thermal efficiency of the Rankine rifle.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to increase the pressure and temperature at which the feed water evaporates into steam for a heat supply fluid having a predetermined temperature range that is passed through the feed water in a heat exchange relationship. The objective is to improve the Rankine cycle thermal efficiency of power generation fusion reactors, pressurized water reactors, sodium- or organic fluid-cooled hyperstatic breeder reactors, and steam generation and reheating equipment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a graph depicting the relationship between temperature and percentage of heat transferred in a steam generator in order to illustrate the advantages obtained by the present invention. The temperature increases from the bottom to the top of the vertical axis. In the graph of FIG. 1, 10 is a graph curve showing the temperature range of heat imparted by the heat supply fluid to water and steam to supply superheated steam to the steam turbine. Note that the heat supply fluid temperature range graph curve is a straight line with an upward slope to the right.

These temperatures of the heat supply fluid limit the humidity at which the supply water evaporates and steam 2 is generated. Height 12 represents a typical fish air-water cycle. The water is preheated in the upwardly sloping line section 14 from points 16 to 18, then the water evaporates at a constant temperature to generate steam in the line section 20 from points 18 to 22, and the resulting saturated steam is , is heated in the upwardly sloping line section 24 from points 22 to 26. Temperature T of line section 20 where water evaporates and generates saturated steam
1 is limited by the temperature T2 at point 28 of the heat supply fluid, where evaporation of the feed water begins.

Therefore, point 28 can be considered a "pinch point",
The temperature difference 'r, -'r1 can be regarded as a "pinch point ΔT".

Since the temperature curve 10 of the heat supply fluid slopes upwards towards the right side of the graph, it is clear that if the pinch point can be moved to the right, the temperature at which evaporation occurs can be increased. .

It is indicated by line 30. That is, in the line 30, the feed water is preheated in the line section 32 from points 16 to 34, and the water emits 7'A at a constant temperature in the line section from points 34 to 40, producing saturated steam. Superheating of the saturated steam takes place in line section 38 from points 40 to 26.

In the steam-water cycle represented by line 30, the pinch point is point 42, and for line 10 (light temperature TI
Allows evaporation at higher temperatures'rs.

The object of the invention is to increase the temperature at which water is evaporated to create saturated steam within the temperature limits of the heat supply fluid, as indicated by the degree T3. An embodiment of the device n of the invention for achieving such high temperatures will now be described.

Referring to FIG. 2, a steam generation and reheating apparatus 50 of the present invention for a fusion reactor power plant is schematically illustrated. In such plants, an intermediate lithium lead-fluid is passed through conduit 51 to remove thermal energy from the core or blanket 53 and to absorb neutrons and thereby produce tritium fuel. Can be used. Most of the tritium is then separated from the lithium-lead for use as fuel, but some of the tritium diffuses through the tube wall. To prevent the small amount of tritium that diffuses through each ear from escaping from the enclosed parts of the plant, organic materials are used to capture the lithium-lead tritium that diffuses through the wall. At the same time,
Heat is removed from the lithium-lead by the organic material for use as a heat supply fluid. The organic fluid used to remove heat from the lithium-lead (heat supply fluid) is preferably a fluid, such as polyphenyl, which disintegrates at temperatures higher than those normally encountered by the fluid. , any suitable heat supply fluid may be used. The organic fluid is lithium-ionized in the heat exchanger 55.
The absorption of thermal energy from the lead results in a temperature of 421° C. (790° C.) in the example illustrated herein. This organic fluid is then passed through a steam generation and reheating device 50 which imparts thermal energy to the water and steam to create steam, which is then reheated and cooled to a temperature of 627°C (62°?). do. This temperature range IL for organic fluids? 1 is indicated by an upwardly sloping straight line 52 in the graph of FIG. The corresponding lithium-lead temperature range is indicated by an upwardly sloping straight line 54 corresponding to straight line 52.

Referring again to FIG. 2, feed water is passed through conduit 58 by means such as feed water pump 56 to a temperature of 246°C (
475? ) is supplied to the first economizer 60 at a temperature of
From there, it is supplied through a conduit 62 to a second economizer 64, and after being preheated by the α1 and 81!2 economizers, it is sent through a conduit R66 to an evaporator 68, where it is further heated and evaporated. 205℃ (401'F)
It generates saturated steam at a constant temperature of 17.2 Mpa, (megapascals). In the evaporator 68 the saturated steam is separated from the water and sent through conduit 70 to a superheater 72 where it is given further thermal energy to reach a temperature of 385° C. (725?) and 16,55 M
The superheated steam is then passed through conduit 74 to a high pressure heat engine, such as high pressure turbine 76, where it expands while passing through the turbine. In order to improve the quality of the exhaust steam from the high pressure turbine to a quality suitable for supply to an intermediate pressure heat engine such as intermediate pressure turbine 78, the saturated and .70 Mpa (70kp/
The exhaust steam at a pressure of EE) cm2 absolute is passed through conduit 80 to a first reheating means, such as a reheater 82, where it is provided with additional thermal energy and is suitable for supplying to the intermediate pressure turbine 78. a temperature of 343°C (650?) and 6
．． High quality (i.e., superheated) steam of 9 MPa (70 kg 7 cm2 absolute) is passed through conduit 84 to intermediate pressure turbine 78, where it is expanded again for additional reduction during passage through the turbine.

In order to increase the quality of the exhaust steam from the intermediate pressure turbine 78 to a quality suitable for supplying to a low pressure heat engine such as the low pressure turbine 86, a saturated and 172 Mpa
The exhaust steam at a pressure of (18 units/unit 2 absolute pressures)
8 to a second reheating means such as second stage reheater 94, conduit 92 and second stage reheater 94 to provide additional thermal energy suitable for supply to low pressure turbine 86. temperature of 345°C (ssoy) and 1.72
It is made into high quality steam of Mpa (18 kg 7 cm" absolute) and is sent through a 2!Z tube 96 to a low pressure turbine 86 where it expands and performs additional work while passing through the turbine.

Steam discharged from the low pressure turbine 86 is fed through conduit 98 to a condenser 100 to be condensed and then returned to the feed water pump 56 through conduit 102 and appropriate feed water addition and treatment equipment (not shown). and the cycle repeats.

In a conventional steam-water cycle, the organic fluid is diverted in parallel streams to a reheater and superheater to provide its thermal energy, and then passed in series to an evaporator and economizer. In order to increase the evaporation temperature of water in the evaporator 68 so as to increase the thermal efficiency of the Rankine cycle compared to the evaporation temperature in such conventional steam-water cycles, according to the present invention, the organic fluid is Provides thermal energy to the feed water in the first and second economizers 60, 64, as well as the evaporator 68 and superheater 72.
The exhaust vapor in the reheater 82.90.94 also imparts thermal energy after passing through the organic fluid, so that of the available thermal energy in the organic fluid, the fluid is transferred to the evaporator 68 and the superheater. 72 to make it possible to increase the percentage of thermal energy given for preheating of the feed water and reheating of the exhaust steam. To enable such organic fluid flow, according to the invention, an evaporator 68, a superheater 72, an economizer 60.
64 are separated from each other as shown in FIG. Thereby, the "pinch point" shown at 104 in FIG. The feed water can be evaporated at a high constant temperature.

Referring again to FIG. 2, the organic fluid is 421
superheater 72 through conduit 106 at a temperature of (below 790°C)
In the superheater, the steam is passed through in a heat exchange relationship with the saturated steam from the steamer A 68 to create superheated steam. The organic fluid exits superheater 72 through conduit 108 at a temperature of 407° C. (below 765) and enters evaporator 6 as a series stream.
8 and passed in heat exchange relationship with preheated feed water in the evaporator to evaporate the feed water and create saturated steam. After imparting thermal energy to the feed water in evaporator 68, the organic fluid passes through conduit 110 to a temperature of 373°C (773°C).
03 below) exits the evaporator. According to the present invention, the organic fluid is then heated by reheating means including a reheater 82.90.94 and first and second economizers 60.6.
4 in parallel flow and in heat exchange relationship with both the feed water and the exhaust steam from the turbine. Specifically, a portion of the organic fluid from evaporator 68 is sent to second economizer 64 through conduit 112. The remainder of the organic fluid is routed through conduit 114 and directed as parallel streams through conduits 116 and 118 to second reheater stage 94 and first heating 'a82, respectively, to further increase the thermal efficiency of the Rankine cycle. It will be destroyed. The organic fluid is passed through conduits 120, 122 from the second economizer 64, the second stage 94 of the second reheater and the first reheater 82, respectively, at a temperature of 342°C (648?).
．． 124 and joins a common conduit 126;
Again in parallel flows through leads 128 and 130 to the first economizer 60 and the first stage 90 of the second reheater, respectively. Compassionate fluid (well, the first economizer 60
and 327°C from the first stage 90 of the second reheater, respectively.
(620'F), flows through heat exchangers 132 and 134, joins in a common conduit 136, returns through conduit 136 to heat exchanger 55, and lithium-
The lithium-lead is passed through in heat exchange relationship with the lead, receiving thermal energy again from the lithium-lead, and is sent back to the superheater 72 through conductor 1106 to repeat the cycle.

The number of economizers and reheaters can be increased or decreased as needed. Furthermore, any suitable fluid such as liquid sodium, other organic fluids, liquid metals, oil, etc. can be used as the heat supply fluid. It will also be apparent to those skilled in the art that appropriate valves and devices (not shown) for flow control may be provided within each conduit.

How the temperature for evaporating water to create saturated steam is increased by the present invention is shown in FIG. In the graph of FIG. 3, the preheating of the feed water in the first economizer 60 is represented by the line section 138 from points 140 to 142 and the discharge in the first stage 90 of the second reheater. Steam reheating is indicated by dotted line section 144 from points 146 to 142. Additional preheating of the feed water in the second economizer 64 occurs from point 142 to 1
The reheating of the exhaust steam in the second stage 94 of the second reheater as well as the reheating of the exhaust steam in the first reheater 82 is represented by a line section 148 from point 142 to 15
It is represented by the dotted line section 152 up to 4. Point 1
04 is the "pinch point" which indicates the temperature limit when water is evaporated. A constant temperature line section 156 from points 150 to 158 shows the evaporation of the feed water within the steamer@468.

A line section 160 from points 158 to 160 is the superheater 72
represents the superheating of saturated steam within a Note that approximately 50% of the available thermal energy in the organic fluid is utilized for preheating the feed water and reheating the steam discharged from the high pressure and intermediate pressure turbines. if,
Significantly less than 50% of the available thermal energy of the organic fluid would be delivered in parallel streams to the superheater and reheater before being delivered to the evaporator and economizer, according to conventional techniques. Since only the thermal energy of the eel can be used to preheat the feed water, the ``pinch point
D4 moves to the left in the graph of FIG. In other words, the degree of evaporation of the supplied water is considerably reduced.

On the other hand, the steam generation-reheating device 50 of the present invention,
The evaporation temperature of the feed water can be increased to increase the thermal efficiency of the Rankine cycle.

The method of the invention comprises the steps of: passing a heat supply fluid through a superheater in heat exchange relationship with the saturated steam to superheat the saturated steam for delivery to a heat engine; after passing through the superheater, passing the heat supply fluid through an evaporator in heat exchange relationship with preheated feed water to create saturated steam for delivery to the superheater; After passing the heat supply fluid through the evaporator, the heat supply fluid is passed in parallel flow through economizer means and reheater means to preheat the feed water for delivery to the evaporator, and at least A steam generation and reheating method is provided, which comprises a step of reheating exhaust steam from one heat engine for feeding to a lower pressure heat engine.

[Brief explanation of the drawing]

FIG. 1 is a graph of temperature versus heat transfer illustrating the advantages provided by the present invention over conventional steam-water cycles;
The figure is a schematic diagram of the steam generation/reheating device of the present invention, and FIG. 6 is a graph showing the temperature versus heat transfer amount for the device of FIG. 2. 55: Heat exchanger 60: First economizer 64: Second eco/miser 68: Evaporator 70: Superheating 8g 76: Heat engine (high pressure steam turbine) 78: Heat engine (intermediate pressure steam turbine) 82: Reheater 86 : Heat engine (low pressure steam turbine) 90: First stage reheater 94: Second stage reheater Reprint of drawing (no change in content) FIG1 FIG, 3 Procedural sleeve formal document (method) % formula % Incident display Patent Application No. 59665 of 1983 is the title of the invention.Relationship with the steam generation/reheating method and device amendment person. Sun---Sunichi Go1〒Tochiba? Cold force for moan T 11f-no t 1! Required for lido ==--Additional 1 [:, Contents of the target hydraulic pressure The engraving of the drawing as shown in the attached sheet (no changes to the contents)

Claims (1)

[Claims] 1) Evaporator means for evaporating feed water to generate saturated steam; superheater means for superheating the saturated steam for delivery to the heat engine; and the heat engine. at least one reheater means for reheating the exhaust steam from the for delivery to the lower pressure heat engine; and an economizer for preheating the feed water before delivery to the evaporator means. means for communicating a heat supply fluid in series through said superheater means and said evaporator means in heat exchange relationship with said steam and water; steam generation and reheating apparatus comprising conduit means for passing said reheater means and economizer means in parallel and in heat exchange relation to said discharged steam and feed water after exiting said steam generator means; 2) The steam generation/reheating device according to claim 1, comprising a thermal energy imparting means for imparting thermal energy from a nuclear reactor to the heat supply fluid. 3) The heat engine is a high pressure a steam turbine and an intermediate D-turbine, said lower pressure heat engine being a low pressure steam turbine, and said reheater means for delivering exhaust steam from said high pressure steam turbine to an intermediate UE, steam turbine. a first stage reheater and a second stage reheater for reheating exhaust steam from the intermediate pressure steam turbine for delivery to the low pressure steam turbine. , the economizer means includes a first economizer and a second economizer, and the conduit means for parallel flow directs the heat supply fluid to the second economizer;
a second stage reheater and a conduit for passing in parallel flow said reheater for exhaust steam from a high pressure steam turbine, a second economizer, a second benefit heater, and exhaust steam of the high pressure steam turbine; Steam generation according to claim 2, further comprising a conduit for flowing heat supply fluid from the reheater through the first economizer and the first stage reheater in parallel.・Reheating device. 4) said evaporator means, superheater means and economizer means are separate from each other, and a conduit connecting the economizer means to the evaporator means for delivering preheated feed water to the evaporator means; 3. A steam generation and reheating device as claimed in claim 2, further comprising a conduit connecting to the superheater means, such as the evaporator means, for delivering saturated steam to the superheater means. 5) The steam generation/reheating device according to claim 1, further comprising thermal energy applying means for applying thermal energy from a fusion reactor to the heat supply fluid. 6) The thermal energy imparting means includes a means for imparting thermal energy of a nuclear fusion reaction to an intermediate tritium-producing fluid, and a means for imparting energy from the intermediate tritium-producing fluid to the heat supply fluid. and wherein the heat supply fluid is of a type t+: 1, wherein the heat supply fluid captures tritium to prevent it from escaping from the enclosed parts of the fusion reactor plant.
Steam generation/reheating equipment. 7) The steam generation/reheating device according to claim 6, wherein the heat supply fluid is an organic fluid. 8) The steam generation/reheating device according to claim 6, wherein the heat supply fluid is polyphenyl, and the intermediate tritium producing fluid in +iiJ is lithium-lead. 9) The heat engine includes a high pressure steam turbine and an intermediate B3F
i% turbine, the lower pressure heat engine is a low pressure steam turbine, and the reheating means reheats exhaust steam from the high pressure steam turbine for delivery to an intermediate pressure steam turbine. a first stage reheater and a first stage reheater for reheating exhaust steam from the intermediate pressure steam turbine for feeding to the low pressure steam turbine;
a stage reheater, the economizer means comprising a first economizer and a second economizer, and the conduit means for parallel flow directs the heat supply fluid to the second economizer and the second stage reheater. a second economizer, a second stage reheater, and said reheater for exhaust steam from the high pressure steam turbine in parallel flow; The steam generation/reheating device according to claim 8, further comprising a conduit for flowing the heat supply fluid from the reheater through the first economizer and the first stage reheater in parallel. . 10) said evaporator means, superheater means and economizer means are separate from each other, and a conduit connecting the economizer means to the evaporator means for delivering preheated feed water to the evaporator means; 10. Steam generation and reheating apparatus as claimed in claim 9, further comprising a conduit connecting the evaporator means to the superheater means for delivering saturated steam to the superheater means. 11) The heat engine is a high pressure steam turbine or a turbine, the lower pressure heat engine is a low pressure steam turbine, and the reheater means converts exhaust steam from the high pressure steam turbine into -11 a reheater for reheating the intermediate pressure steam turbine for delivery to the intermediate pressure steam turbine; and a first stage reheater for reheating the exhaust steam from the intermediate pressure steam turbine for delivery to the low pressure steam turbine. a heater and a second stage reheater, the economizer means including a first economizer and a second economizer, and the conduit means for parallel flow directing the heat supply fluid to the second economizer;
a conduit for passing in parallel flow a second stage reheater and a pre-dC reheater for exhaust steam from the high pressure steam turbine; 2. The method of claim 1, further comprising a conduit for communicating heat supply fluid from the reheater for exhaust steam through the first economizer and the first stage reheater in parallel. Steam generation/reheating equipment. 12) said evaporator means, superheater means and economizer means are separated from each other, and a conduit connecting the economizer means to the evaporator means for delivering preheated feed water to the evaporator means; The steam generation/reheating device according to claim 11, wherein a dedicated pipe is provided for connecting the evaporator means to the superheating means for feeding saturated steam to the superheater means. 13) The mJ evaporator means, the superheater means and the economizer means are hidden from each other, and a dedicated pipe connects the economizer means to the evaporator kR means for delivering preheated feed water to the evaporator means. and a steam generation/reheating device according to paragraph 1 of Il'ii m of the Special Fraud Request, which is provided with a dedicated pipe for connecting the evaporator means to the superheater means in order to feed saturated steam to the superheater means. . 14) passing a heat supply fluid through a superheater in a heat exchange relationship with the saturated steam to superheat the saturated steam for delivery to the heat engine; and passing the heat supply fluid through the superheater. passing the heat supply fluid through the evaporator in heat exchange relationship with preheated feed water to create saturated steam for delivery to the superheater; and passing the heat supply fluid through the evaporator. the heat supply fluid is passed in parallel flow through economizer means and reheater means to preheat the feed water for delivery to the evaporator; A method of steam generation and reheating that consists of the step of reheating exhaust steam for delivery to a lower pressure heat engine. 15) The steam generation/reheating method according to claim 14, which includes the step of applying thermal energy from a nuclear reaction to the heat supply fluid. 16) A special feature that includes the step of imparting thermal energy from a nuclear fusion reaction to the heat supply fluid.
The steam generation/reheating method described in Section s14. - 17) said step of passing the heat supply fluid through the economizer means and the reheater means includes a second economizer and a reheater for reheating the exhaust steam from the intermediate pressure steam turbine for delivery to the low pressure steam turbine; Heat t1 (feed fluid is passed through the second stage of the heater and a reheater for reheating the exhaust steam from the high pressure natural air turbine for delivery to the intermediate pressure steam turbine) in parallel. , then passing the heat supply fluid through a first economizer and a reheater for reheating the exhaust steam of the intermediate pressure steam turbine in parallel. 15. The steam generation/reheating method according to claim 14. 18) The steam generation/reheating method according to claim 17, including the step of applying thermal energy from a nuclear reaction to the heat supply fluid. 19) The steam generation/reheating method according to claim 17, which includes a step of imparting thermal energy from a nuclear fusion reaction to the heat supply fluid.